review refactor: CompilationUnit should return unmodifiable collection

src/main/java/spoon/reflect/cu/CompilationUnit.java

@@ -72,6 +72,11 @@ enum UNIT_TYPE {
 	 */
 	void setDeclaredTypes(List<CtType<?>> types);
 
+	/**
+	 * Add a type to the list of declared types
+	 */
+	void addDeclaredType(CtType type);
+
 	/**
 	 * Gets the declared module if the compilationUnit is "module-info.java"
 	 */

src/main/java/spoon/support/compiler/jdt/ParentExiter.java

@@ -75,6 +75,7 @@
 import spoon.reflect.code.BinaryOperatorKind;
 import spoon.reflect.code.CtThisAccess;
 import spoon.reflect.code.CtLocalVariable;
+import spoon.reflect.cu.CompilationUnit;
 import spoon.reflect.cu.SourcePosition;
 import spoon.reflect.declaration.CtAnnotation;
 import spoon.reflect.declaration.CtElement;
@@ -776,7 +777,10 @@ public void visitCtPackage(CtPackage ctPackage) {
 			}
 			ctPackage.addType((CtType<?>) child);
 			if (child.getPosition() != null && child.getPosition().getCompilationUnit() != null) {
-				child.getPosition().getCompilationUnit().getDeclaredTypes().add((CtType<?>) child);
+				CompilationUnit cu = child.getPosition().getCompilationUnit();
+				List<CtType<?>> declaredTypes = new ArrayList<>(cu.getDeclaredTypes());
+				declaredTypes.add((CtType<?>) child);
+				cu.setDeclaredTypes(declaredTypes);
 			}
 			return;
 		}

src/main/java/spoon/support/reflect/cu/CompilationUnitImpl.java

@@ -31,6 +31,7 @@
 import java.nio.file.Paths;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
 
@@ -47,11 +48,6 @@ public class CompilationUnitImpl implements CompilationUnit, FactoryAccessor {
 
 	CtModule ctModule;
 
-
-	public List<CtType<?>> getDeclaredTypes() {
-		return declaredTypes;
-	}
-
 	File file;
 
 	@Override
@@ -81,10 +77,12 @@ public UNIT_TYPE getUnitType() {
 		}
 	}
 
+	@Override
 	public File getFile() {
 		return file;
 	}
 
+	@Override
 	public CtType<?> getMainType() {
 		if (getFile() == null) {
 			return getDeclaredTypes().get(0);
@@ -103,8 +101,20 @@ public CtType<?> getMainType() {
 						+ getDeclaredTypes());
 	}
 
+	@Override
+	public List<CtType<?>> getDeclaredTypes() {
+		return Collections.unmodifiableList(declaredTypes);
+	}
+
+	@Override
 	public void setDeclaredTypes(List<CtType<?>> types) {
-		this.declaredTypes = types;
+		this.declaredTypes.clear();
+		this.declaredTypes.addAll(types);
+	}
+
+	@Override
+	public void addDeclaredType(CtType type) {
+		this.declaredTypes.add(type);
 	}
 
 	@Override

src/test/java/spoon/test/compilationunit/TestCompilationUnit.java

@@ -1,18 +1,24 @@
 package spoon.test.compilationunit;
 
+import org.apache.commons.lang3.StringUtils;
 import org.junit.Test;
 import spoon.Launcher;
 import spoon.reflect.cu.CompilationUnit;
 import spoon.reflect.declaration.CtPackage;
 import spoon.reflect.declaration.CtType;
+import spoon.support.JavaOutputProcessor;
 import spoon.test.api.testclasses.Bar;
 
 import java.io.File;
+import java.io.IOException;
 import java.nio.charset.Charset;
 import java.nio.file.Files;
 import java.util.Collections;
+import java.util.List;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
 
 /**
  * Created by urli on 18/08/2017.
@@ -71,4 +77,54 @@ public void testGetUnitTypeWorksWithCreatedObjects() {
         cu.setDeclaredTypes(Collections.singletonList(launcher.getFactory().createClass()));
         assertEquals(CompilationUnit.UNIT_TYPE.TYPE_DECLARATION, cu.getUnitType());
     }
+
+    @Test
+    public void testCompilationUnitDeclaredTypes() throws IOException {
+        // contract: the list of declared types should be unmodifiable
+        File resource = new File("./src/test/java/spoon/test/model/Foo.java");
+        final Launcher launcher = new Launcher();
+        launcher.addInputResource(resource.getPath());
+        launcher.buildModel();
+
+        CompilationUnit cu = launcher.getFactory().CompilationUnit().getOrCreate(resource.getCanonicalPath());
+        assertEquals(3, cu.getDeclaredTypes().size());
+
+        List<CtType<?>> typeList = cu.getDeclaredTypes();
+        try {
+            typeList.remove(0);
+            fail();
+        } catch (UnsupportedOperationException e) {
+            // do nothing
+        }
+    }
+
+    @Test
+    public void testAddDeclaredTypeInCU() throws IOException {
+        // contract: when a type is added to a CU, it should also be pretty printed in cu mode
+        File resource = new File("./src/test/java/spoon/test/model/Foo.java");
+        final Launcher launcher = new Launcher();
+        launcher.setArgs(new String[]{  "--output-type", "compilationunits"});
+        launcher.addInputResource(resource.getPath());
+        launcher.setSourceOutputDirectory("./target/cu-onemoretype");
+        launcher.buildModel();
+
+        CompilationUnit cu = launcher.getFactory().CompilationUnit().getOrCreate(resource.getCanonicalPath());
+        assertEquals(3, cu.getDeclaredTypes().size());
+
+        CtType typeBla = launcher.getFactory().Class().create("spoon.test.model.Bla");
+        cu.addDeclaredType(typeBla);
+
+        assertEquals(4, cu.getDeclaredTypes().size());
+
+        launcher.prettyprint();
+
+        File output = new File("./target/cu-onemoretype/spoon/test/model/Foo.java");
+        List<String> lines = Files.readAllLines(output.toPath());
+
+        String fullContent = StringUtils.join(lines, "\n");
+        assertTrue(fullContent.contains("public class Foo"));
+        assertTrue(fullContent.contains("class Bar"));
+        assertTrue(fullContent.contains("class Baz"));
+        assertTrue(fullContent.contains("class Bla"));
+    }
 }